Articles

Access the latest knowledge in applied science, electrical engineering, computer science and information technology, education, and health.

Advanced Search
Filter Icon

Filters article

Years

FAQ Arrow
Single Year
Range Year
0
0

Source Title

FAQ Arrow

Authors

FAQ Arrow

29,082 Article Results

Improved Timing Estimation Using Iterative Normalization Technique for OFDM Systems

10.11591/ijece.v7i2.pp905-911
Suyoto Suyoto , Iskandar Iskandar , Sugihartono Sugihartono , Adit Kurniawan
Conventional timing estimation schemes based on autocorrelation experience performance degradation in the multipath channel environment with high delay spread. To overcome this problem, we proposed an improvement of the timing estimation for the OFDM system based on statistical change of symmetrical correlator. The new method uses iterative normalization technique to the correlator output before the detection based on statistical change of symmetric correlator is applied. Thus, it increases the detection probability and achieves better performance than previously published methods in the multipath environment. Computer simulation shows that our method is very robust in the fading multipath channel
Volume: 7
Issue: 2
Page: 905-911
Publish at: 2017-04-01

DARE Algorithm: A New Security Protocol by Integration of Different Cryptographic Techniques

10.11591/ijece.v7i2.pp1032-1041
John Mark Espalmado , Edwin Arboleda
Exchange of information between computer networks requires a secure communications channel to prevent and monitor unauthorized access, modification and denial of the computer network. To address this growing problem, security experts sought ways to advance the integrity of data transmission. Security Attacks compromises the security and hence hybrid cryptographic algorithms have been proposed to achieve safe service in the proper manner, such as user authentication and data confidentiality. Data security and authenticity are achieved using these algorithms. Moreover, to improve the strength and cover each algorithm’s weaknesses, a new security algorithm can be designed using the combination of different cryptographic techniques. This design uses Digital Signature Algorithm (DSA) for authentic key generation, Data Encryption Standard (DES) for key scheduling, and Advanced Encryption Standard (AES) and Rivest–Schamir–Adleman Algorithm (RSA) in encrypting data. This new security algorithm has been proposed for improved security and integrity by integration of these cryptographic techniques.
Volume: 7
Issue: 2
Page: 1032-1041
Publish at: 2017-04-01

Comparative Analysis of Time and Physical Redundancy Techniques for Fault Detection

10.11591/ijeecs.v6.i1.pp66-71
Namita Arya , Amit Prakash Singh
The integration level in today’s world is continuously increasing in VLSI chips. VLSI circuit verification is a major challenge in these days. Integration capacity of VLSI circuits mimics the testing complexity of circuits. There is a significant chunk of the testing cost with respect to the whole fabrication prices. Hence it is important to cut down the verification cost. Time required during testing is a main factor for the cost of a chip. This time is directly proportional to the number of testing in the circuitry. So the test set should be very small. There is one way to generate a small test set is to compact a large test set parameters. The main drawback of the compaction results on the quality of the original test set. This aspect of compaction has motivated the work present here with some methods of fault detection and avoidance techniques via redundancy logic as Time redundancy and physical redundancy.
Volume: 6
Issue: 1
Page: 66-71
Publish at: 2017-04-01

Synthesis of Germanium Dioxide Microclusters on Silicon Substrate in Non-aqueous Solution by Electrochemical Deposition

10.11591/ijeecs.v6.i1.pp193-199
Mastura Shafinaz Zainal Abidin , Shahjahan Shahjahan , Abdul Manaf Hashim
We report the formation of crystalline germanium dioxide (GeO2) microclusters on n-Si (100) electrodeposited in non-aqueous electrolyte (a mixture of 5 vol.% germanium tetrachloride (GeCl4) and dipropylene glycol (C6H14O3) ) at current density of 20 mA/cm2 for 200 sec. Pt, C and Ge are used as an anode while Si acts as a cathode. Field- emission scanning electron microscopy (FESEM) images show that the deposited GeO2 microclusters are having rounded-mushroom-shaped particles with the smallest size of 660 nm. Energy dispersive x-ray (EDX) spectra reveal that the particles are only composed of Ge and O elements. Raman spectra confirm the formation of crystalline GeO2 with trigonal bonding structures in all samples. The photoluminescence (PL) spectra show two significant emission peaks in visible range at 2.27 eV and 2.96 eV, which seems to be attributed by GeO2 and Si defects. C6H14O3 seems to contribute to the formation of GeO2 due to its hygroscopic nature. Such microcluster structures shall provide some potential applications for electronic and optical devices on Si platform.
Volume: 6
Issue: 1
Page: 193-199
Publish at: 2017-04-01

Layout Effects on High Frequency and Noise Parameters in MOSFETs

10.11591/ijeecs.v6.i1.pp88-96
Asmaa Nur Aqilah Zainal Badri , Norlaili Mohd Noh , Shukri bin Korakkottil Kunhi Mohd , Asrulnizam Abd Manaf , Arjuna Marzuki , Mohd Tafir Mustaffa
This study reviews related studies on the impact of the layout dependent effects on high frequency and RF noise parameter performances, carried out over the past decade. It specifically focuses on the doughnut and multi- finger layouts. The doughnut style involves the polygonal and the 4- sided techniques, while the multi-finger involving the narrow-oxide diffusion (OD) and multi-OD. The polygonal versus 4-sided doughnut, and the narrow-OD with multi-fingers versus multi-OD with multi- fingers are reviewed in this study. The high frequency parameters, which are of concern in this study, are the cut- off frequency (fT) and the maximum frequency (fMAX), whereas the noise parameters involved are noise resistance (RN) and the minimum noise figure (NFmin). In addition, MOSFET parameters, which are affected by the layout style that in turn may contribute to the changes in these high frequency, and noise parameters are also detailed. Such parameters include transconductance (Gm); gate resistance (Rg); effective mobility (μeff); and parasitic capacitances (cgg and cgd). Investigation by others has revealed that the polygonal doughnut may have a larger total area in comparison with the 4- sided doughnut. It is also found by means of this review that the multi-finger layout style with narrow-OD and high number of fingers may have the best performance in fT and fMAX, owing partly to the improvement in Gm, μeff, cgg, cgd and low frequency noise (LFN). A multi-OD with a lower number of fingers may lead to a lower performance in fT due to a lower Gm. Upon comparing the doughnut and the multi-finger layout styles, the doughnuts appeared to perform better than a standard multi-finger layout for fT, fMAX, Gm and μeff but are poorer in terms of LFN. It can then be concluded that the narrow-OD multi-finger may cause the increase of cgg as the transistor becomes narrower, whereas a multi-OD multi-finger may have high Rg and therefore may lead to the increase of fT and fMAX as the transistor becomes narrower. Besides, the doughnut layout style has a higher Gm and fT, leading to larger μeff from the elimination of shallow trench isolation (STI) stress.
Volume: 6
Issue: 1
Page: 88-96
Publish at: 2017-04-01

Modeling and Simulation of VSI Fed Induction Motor Drive in Matlab/Simulink

10.11591/ijece.v7i2.pp584-595
D. Uma , K. Vijayarekha
The theory of reference frames and switching functions are effective in analyzing the performance of the induction motor fed from VSI (Voltage Source Inverter). In this work, mathematical model of Adjustable Speed Drive (ASD) is developed by taking synchronous reference frame equations for induction motor, switching function concept for VSI and non-switching concept for diode bridge rectifier.  The developed model is implemented using MATLAB/Simulink as it is an important tool for the validation of the proposed model. The performance of induction motor is analysed for different frequencies. The developed model is tested for the steady state behavior of machine drive. The proposed mathematical model is validated by the simulation results.
Volume: 7
Issue: 2
Page: 584-595
Publish at: 2017-04-01

Focusing Properties of a Modified Retarding Structure for Linear Electron Accelerators

10.11591/ijece.v7i2.pp741-747
Vladimir Kuz'mich Shilov , Aleksandr Nikolaevich Filatov , Aleksandr Evgen'evich Novozhilov
When using accelerators in industry and medicine, important are the dimensions of the device used, especially the radial ones. In the linear electron accelerators based on a biperiodic retarding structure, which operates in the standing wave mode, there is a possibility to provide focusing of the accelerated particles with the help of high-frequency fields without the use of external focusing elements. In the accelerating cell, due to the presence of the far protruding drift sleeves, the electric field lines become strongly curved, which leads to the appearance in the regions adjacent to these sleeves of a substantial in magnitude radial component of the electric field. The particles entering the accelerating gap experience the action of a force directed toward the axis of the system, and at the exit, of a force directed away from the axis. Under certain conditions, alternation of the focusing and defocusing fields can lead to a general focusing effect. In the paper we study the focusing properties of a modified biperiodic structure with standing wave. The main attention is paid to the possibility of using the focusing properties of the electromagnetic accelerating field for guiding the electron beam through the aperture of the accelerating system, which will lead to a significant reduction in the accelerator sizes. The proposed method can be applied in the calculation and design of linear electron accelerators.
Volume: 7
Issue: 2
Page: 741-747
Publish at: 2017-04-01

Dielectric Strength Improvement of Natural Ester Insulation Oil via Mixed Antioxidants: Taguchi Approach

10.11591/.v7i2.pp650-658
Sharin Ab Ghani , Zulkarnain Ahmad Noorden , Nor Asiah Muhamad , Hidayat Zainuddin , Muhammad Ilman Hakimi Chua Abdullah , Imran Sutan Chairul
Recently, natural ester insulation (NEI) oils are found to be the best candidates to replace mineral-based insulation oils for oil-immersed transformer applications. However, NEI oils are prone to oxidation due to their poor oxidative stability which can be improved by adding antioxidants into the oils. Latest studies have also shown that the use of selected antioxidants improves the AC breakdown voltage (BdV) of NEI oils. However, the experiments in previous studies were designed using the conventional one-factor-at-a-time (OFAT) method, which requires a large number of samples to be tested in order to determine the optimum response. Thus, a Taguchi-based designed experiment is introduced in this study in replacement of the OFAT method. It is found that this method is capable of determining the optimum concentrations of propyl gallate (PG) and citric acid (CA) which will maximize the AC BdV and improve the oxidative stability of the NEI oil. An AC breakdown voltage test is conducted in accordance with the ASTM D1816 standard using Megger OTS60PB portable oil tester, in which the electrode gap distance is kept fixed at 1 mm. The results indicate that the addition of PG and CA antioxidants increases the AC BdV of the rapeseed-based NEI oil. It is found that the optimum concentrations of PG and CA antioxidant is 0.05 and 0.25 wt.%, respectively. Lastly, the model developed in this study is analysed using analysis of variance (ANOVA). Validation test is also conducted on the optimized NEI oil to determine its dielectric strength and oxidative stability.
Volume: 7
Issue: 2
Page: 650-658
Publish at: 2017-04-01

Harmonic Suppression of Shunt Hybrid Filter Using LQR-PSO based

10.11591/ijece.v7i2.pp869-876
Nor Shahida Hasan , Norzanah Rosmin , Saifulnizam Abd Khalid , Dygku. Asmanissa Awg. Osman , Baharuddin Ishak , Aede Hatib Mustaamal
In linear quadratic regulator (LQR), two different weighting matrices play an important role in presenting the performance of this controller. Instead of using classic common approach, which is trial and error method, this study proposes a particle swarm optimization (PSO) algorithm to track the best solution of the weighting matrices. The proposed algorithm is tested on shunt hybrid active power filter (APF) to mitigate the harmonic contents in voltage and current signals in a nonlinear load system. The modeling work of this proposed system is simulated using MATLAB/Simulink software. From the simulation, the obtained results proved that using PSO in tuning the LQR controller produce smoother nonlinear voltage and current signals. In fact, the amount of current to be injected into network can be reduced up to 95%. Besides, less time is consumed during searching the optimum weighting matrices using the proposed approach.
Volume: 7
Issue: 2
Page: 869-876
Publish at: 2017-04-01

An Adaptive Cross-Layer Architecture to Optimize QoS Provisioning in MANET

10.11591/ijeecs.v6.i1.pp16-25
Asha Asha , G. Mahadevan
Mobile Ad Hoc Network (MANET) is a collection of mobile nodes, which dynamically form a temporary network, without using any infrastructure like wireless access points or base-stations. The provision of QoS guarantees is much more challenging in Mobile Ad hoc Networks. There are many interesting applications such as multimedia services, disaster recovery etc can be supported if Quality-of-Service (QoS) support can be provided for MANETs. But QoS provisioning in MANETs is a very challenging problem when compared to wired IP networks. This is because of unpredictable node mobility, wireless multi-hop communication, contention for wireless channel access, limited battery power and range of mobile devices as well as the absence of a central coordination authority. So, the design of an efficient and reliable routing scheme providing QoS support for such applications is a difficult task. In this paper we studied the challenges and approaches for QoS aware routing techniques.   
Volume: 6
Issue: 1
Page: 16-25
Publish at: 2017-04-01

Novel 9-Steps Automatic AC Voltage Regulator based on Two Step-down Transformers

10.11591/ijece.v7i2.pp576-583
Hussain Attia
A novel design and simulation results of 9-steps automatic AC voltage regulator based on one step-down transformer is presented in this paper. Avoiding the problem of surge at the AC load during controlling jump steps is done through the proposed design. Accurate and smooth controlling function is achieved as well. Instead of the necessity of increasing the number of taps of the used multi tap transformer for wide controlling range of fluctuated AC  supply voltage, the proposed designed adopts using only two step down transformers with 10 Vrms, and 30 Vrms secondary voltages respectively. Through the controlling of the proposed design of AV voltage regulator, the resultant load voltage is equal the AC supply voltage as well as the suitable voltage step which may one of the following voltages; +40V, +30V, +20V, +10V, 0V, -10V, -20V, -30V, -40V. The electronic design is done Multisim software while the electrical circuit connection of step down transformers and relays contacts that is made by using PSIM software for power circuit design.
Volume: 7
Issue: 2
Page: 576-583
Publish at: 2017-04-01

Generator Assessment of Hydro Power Station Adequacy after Reconstruction from Classical to HIS SF6 Substation

10.11591/ijece.v7i2.pp729-740
Srete Nikolovski , Goran Slipac , Emir Alibašić
Reliability analysis of substations and generator assessment of power plant stations are very important elements in a design and maintenance process. This paper presents a generator adequacy assessment of a classical “H” scheme for an open conventional substation, which is often used, and a new HIS - High Integrated Switchgear with SF6 gas isolation. Generator adequacy indices of both types of classical and HIS switchgear were compared and the results showed a high level of reliability and availability of the HIS presented substation. The input data were the annual reports of Croatian TSO-Transmission System Operator (HOPS) and statistics of operation events of Croatian National Electricity (HEP Inc.). For the HIS substation, the input reliability data were used from relevant international literature since only few of HIS substations are installed in Croatia. The generator is modelled with a three-state Markov state space model and Monte Carlo simulations were used for the generator assessment analysis. Adequacy indices LOLP and EDNS were obtained using DIgSILENT software.
Volume: 7
Issue: 2
Page: 729-740
Publish at: 2017-04-01

The Weights Detection of Multi-criteria by using Solver

10.11591/ijece.v7i2.pp858-868
Fachrurrazi Fachrurrazi , Yuwaldi Away , Saiful Husin
Multi criteria, which are generally used for decision analysis, have certain characteristics that relate to the purpose of the decision. Multi criteria have complex structures and have different weights depending upon the consideration of assessors and the purpose of the decision also. Expert’s judgment will be used to detect the criteria weights that applied by assessors. The aim of this study is a model to detect the criteria weights and biases on the subcontractor selection and detecting the significant weights, as decisive criteria. A method, which is used to modeling the weights detection, is the Solver Application. Data, totaling 40 sets, has been collected that consist of the assessor’s assessment and the expert’s judgment. The result is a pattern of weights and biases detection. The proposed model have been able to detect of 20 criteria weights and biases, that consist of 4 criteria in  the total weights of 60% (as decisive criteria) and 16 criteria in the total weights of 40%. A model has been built by training process performed by the Solver, which the result for MSE training is 9.73711e-08 and for MSE validation is 0.00900528. Novelty in the study is a model to detect pattern of weights criteria and biases on subcontractor selection by transferring the expert's judgment using Solver Application.
Volume: 7
Issue: 2
Page: 858-868
Publish at: 2017-04-01

Lyot-based Multi-wavelength Fiber Laser

10.11591/ijece.v7i2.pp981-985
Suhairie Saleh , N. A. Cholan , A. H. Sulaiman , M. A. Mahdi
A multi-wavelength fiber laser which is based on a Lyot filter is experimentally demonstrated. A combination of four-wave mixing in a highly nonlinear fiber and Lyot filter mechanism in the laser cavity is able to generate multi-wavelength with relatively high extinction ratio (ER). At the input current of 100mA, six laser lines with ER more than 5 dB are successfully generated. The wavelength spacing for the multi-wavelength is 0.15nm, corresponding to the characteristics of the Lyot filter used.
Volume: 7
Issue: 2
Page: 981-985
Publish at: 2017-04-01

Diagnosis of Faulty Sensors in Antenna Array using Hybrid Differential Evolution based Compressed Sensing Technique

10.11591/.v7i2.pp961-966
Shafqat Ullah Khan , M. K. A. Rahim , I. M. Qureshi , N. A. Murad
In this work, differential evolution based compressive sensing technique for detection of faulty sensors in linear arrays has been presented. This algorithm starts from taking the linear measurements of the power pattern generated by the array under test. The difference between the collected compressive measurements and measured healthy array field pattern is minimized using a hybrid differential evolution (DE). In the proposed method, the slow convergence of DE based compressed sensing technique is accelerated with the help of parallel coordinate decent algorithm (PCD). The combination of DE with PCD makes the  minimization faster and precise. Simulation results validate the performance to detect faulty sensors from a small number of measurements.
Volume: 7
Issue: 2
Page: 961-966
Publish at: 2017-04-01
1 2 3
...
1938 1939
Show 1508 of 1939

Discover Our Library

Embark on a journey through our expansive collection of articles and let curiosity lead your path to innovation.

Explore Now
Library 3D Ilustration